Motorhome with increased interior ceiling height

ABSTRACT

A vehicle frame with a low profile suitable for attaching directly to an incomplete, preassembled motorized chassis to construct a motorhome. The vehicle frame includes planar bulkheads and a storage area floor that are attached to the frame and to the chassis so as to create a three-dimensional space frame that is highly resistant to bending and twisting forces as well as storage areas that extend the width of the motorhome. The motorhome with the frame mounts a heating, ventilation, and air conditioning (HVAC) system as well as heavy holding tanks within or below the plane of the vehicle frame so as to lower the center of mass of the motorhome to thereby improve vehicle handling and safety. Placement of the HVAC system within and/or below the vehicle frame obviates the need to position HVAC components on the roof of the motorhome thereby further lowering the center of mass and eliminating a source of liquid water condensation above the living space of the motorhome. The vehicle frame attached directly to the chassis further facilitates an interior ceiling height in the motorhome of at least 7′6″ while maintaining a total vehicle height not exceeding 13′6″ as well as facilitating construction of slide-out rooms with interior heights of at least 6′1″ thereby allowing adults of above average height to stand up inside the slide-out rooms.

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/240,270, filed Oct. 13, 2000, entitled Low ProfileVehicle Frame.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to the field of vehicle frames and,in particular, to a high-strength frame suitable for motorhomeconstruction which enables a greater interior ceiling height.

[0004] 2. Description of the Related Art

[0005] Recreational vehicles (RVs) have become an increasingly popularand common means of recreation. RVs are vehicles that include a livingspace inside and can be either self-propelled, as in a motorhome, or candepend on another vehicle for their motive power, as in campers ortrailers. RVs typically provide sleeping areas, cooking facilities, andself-contained water supplies and toilet facilities. More elaborate RVscan include refrigerator/freezer units, showers and/or bathtubs, airconditioning, heaters, built in generators and/or power inverters,televisions, VCRs, and clothes washers and dryers. RVs provide many ofthe amenities of a residential home while on the road away from home andare popular for this reason. RV users will typically use the RV totravel to a recreational area and live in the RV for some period oftime. It is not unusual for people, particularly retired persons, to usean RV as their primary residence. RV users often have families withchildren and, as their trips are often of a recreational nature, willoften invite friends or family along on the trip.

[0006] It can be understood that since an RV will often be used by alarge number of people and often for an extended period of time, the RVmanufacturers and customers will seek as many amenities and as muchinterior living space as possible. A major goal of RV manufacturers andtheir customers is to maximize the amount of usable living space insidetheir RVs. However, the overall size of an RV is limited both by vehiclecode regulations and by practical limitations on what is reasonable todrive and maneuver. Vehicle codes restrict the maximum height, width,and length of vehicles that may be driven on public roads. Also, as avehicle increases in size, it becomes increasingly difficult to driveand can become physically too large to pass through locations that thedriver may wish to go. In addition, as the RV gets physically larger,more fuel is required to move it, which increases the cost of operation.Accordingly, many RVs are provided with slide-out room structures whichare extensible so as to increase the RV's footprint and interior livingspace once the vehicle comes to rest.

[0007] An additional design constraint on the construction and design ofRVs is their overall weight. Since an RV is intended to be mobile,either a integral power plant is provided, as in the case of motorhomes,or a tow vehicle is used to pull or carry the RV, as in the case oftrailers or campers, respectively. The engine and drive-train of anymotive source has an upper design limit on the weight it is capable ofmoving. In addition, the chassis, suspension, wheels, and brakes of amotorhome or tow vehicle also have upper design limits as to how muchweight they can safely accommodate. These weight limits are establishedafter careful engineering analysis and the weight ratings are endorsedand enforced by responsible governmental agencies. Exceeding theestablished weight limits of a power-train or chassis component can leadto excessive wear and failure, unacceptable performance, and exposure toliability in case of an accident.

[0008] A particular issue with the weight of a motorhome is itsdistribution along a vertical axis. The distance of the vehicle's centerof mass from the road surface has a dramatic effect on the handlingcharacteristics of the vehicle. The closer the center of mass is to theroad surface, the shorter the moment arm between the center of mass andthe roll axis of the vehicle. The shorter the moment arm between thecenter of mass and the roll axis of the vehicle, the less tendency thevehicle will have to lean in turns. Leaning in turns is uncomfortablefor the occupants and typically places uneven loads on the tires andsuspensions, compromising turning ability. For these reasons, race cars,for example, are typically built to ride as low to the ground aspossible. Motorhomes, typically being quite tall, often exhibitsignificant leaning in turns. Obviously, the uses and requirements foran RV are quite different than those of a race car, however, within theheight available in a motorhome, the weight should be concentrated aslow as possible. For this reason, heavy items, such as generators,storage and holding tanks for water and fuel, and the engine areoptimally placed low in the chassis.

[0009] Since RVs are mobile structures, they are typically exposed tothe stresses of driving over roads that are in places quite rough. Inaddition, an RV will often have to travel over some distance of dirtsurface to reach a camping space. Since an RV is typically usedoutdoors, it is exposed to the stresses of inclement weather and highwinds. It can be appreciated that structural integrity is highly desiredin an RV. However, the weight and size limitations previously mentionedplace a limit on the strength of an RV. Accordingly, RVs are constructedto be as strong, but as light as possible.

[0010] The chassis of a motorhome is typically constructed on apreassembled steel ladder frame chassis. The chassis is a partiallycomplete vehicle and is generally procured from a manufacturer such asFreightliner or Ford Motor Company. The chassis typically consists oftwo parallel frame rails extending the length of the chassis andinterconnected with several perpendicular cross-braces to form a ladderframe. An engine, transmission, and fuel tank(s) are generally placedbetween the frame rails near one end. Suspension, steering, brake, androad wheel assemblies are attached outboard of the frame rails.

[0011] The coach bodywork, which provides and encloses the living spaceof the motorhome, is typically made from a laminate that can includelight gauge sheet metal, plywood, vinyl, and insulation. The laminate isbuilt to be strong, lightweight, weather resistant, and durable. Thecoach bodywork may also include a supporting framework. The floor of thecoach typically rests indirectly on the chassis frame and the verticalwalls extend upwards from the floor. The roof of the coach rests on anddepends on the vertical walls of the body for structural support.

[0012] A completed motorhome may be up to 45′ long and 3′6″ high in moststates. The chassis is generally on the order of 1′ high and is elevatedsome distance above the ground by the suspension and wheels to provideground clearance for suspension movement and clearing obstacles in theroad. The interior flooring in current art motorhomes is typicallyelevated a significant amount above the upper face of the chassis inorder to facilitate installing ancillary equipment. In addition, manyprior art motorhomes rout cooling or heating air ducts adjacent the roofstructure or mount air-conditioning units on the roof. Under the overallheight limit previously mentioned, these structures in or on the roofintrude into the available interior height envelope and limit the usableinterior vertical space. Current motorhomes typically offer interiorceiling heights of 6′9″ or less. The slide-outs in current artmotorhomes do not typically provide sufficient room inside for adults tostand upright. As the slide-out area is a living space in the extendedposition, it can be appreciated that be forced to stoop or crouch insidethe slide-out is an inconvenience for the users of such motorhomes.

[0013] Placement of air conditioning units and/or ducting in the roofcreates a further difficulty with water condensation. As airconditioning units cool air below the ambient temperature, it will beappreciated that in many conditions the temperature of the airconditioning unit and ducting carrying the cooled air will be below theambient dew point and thus liquid water will condense on the coolsurfaces. If these cool surfaces are located above living areas of themotorhome, as is the case with many current designs, the liquid watercan be readily drawn by gravity into the interior of the motorhome. Itwill be appreciated that liquid water intruding into the interior of themotorhome is an annoyance at best and can damage the structuralintegrity of interior structures as well staining or warping interiorfinishings. Liquid water can also irreparably damage electronicequipment, such as laptop computers, televisions, and VCRs, such aswould often be located in the interior of a motorhome.

[0014] An additional difficulty arises with motorhomes of theconstruction described above when the vehicle drives over rough terrain.Motorhomes are essentially rectangular and are thus susceptible totwisting deflection as opposed to a triangulated structure. Motorhomesof the construction described above are not particularly strong undertorsional forces such as arise when one corner of the vehicle drops orrises compared to the others, for example when a wheel drops into apothole or rut or the vehicle drives over a curb or speed bump at anangle. Such maneuvers “cross-up” the rectangular frame and imposetwisting forces. These forces, exerted over the relatively largedimensions of a typical motorhome, can cause significant displacement inthe coach. This can cause cracks to appear in the coach, jam door andwindow openings, dislodge interior fitments, and generally cause wearand tear on the vehicle.

[0015] From the foregoing, it can be appreciated that there is acontinuing need for a stronger motorhome coach construction that alsoprovides increased interior living space. The structure should not addan excessive amount of weight to the motorhome and should also maintaina low center of gravity to benefit vehicle handling characteristics. Thedesign should position the air conditioning system in such a way thatwater that condenses out during use does not intrude into the interiorof the motorhome.

SUMMARY OF THE INVENTION

[0016] The aforementioned needs are satisfied by the present invention,which in one aspect is a vehicle frame comprising: a plurality ofparallel, elongate rail members extending the length of the frame; aplurality of parallel, elongate cross-tie members arranged perpendicularto the rail members and interconnecting the rail members so as to definea chassis plane and a floor plane; and a plurality of rigid planarmembers fixedly attached along a first edge to the cross-tie and railmembers so as to extend downwards from the chassis plane wherein theinterconnected rail, cross-tie, and planar members together define athree dimensional space frame. In one embodiment, the vehicle framefurther comprises a rigid bottom floor panel substantially parallel tothe chassis plane and attached to a second edge of the planar membersopposite the first edge. The interconnected elongate rail members, crossties, planar members, and bottom floor panel together define a closed,structural box structure. The interconnected planar members and bottomfloor panel also define storage areas that extend substantially thewidth of the vehicle frame.

[0017] In one particular embodiment of the invention, the planar membersare folded along edges of the planar members such that a portion of theplanar members extend substantially perpendicular to the plane of theplanar members so as to define attachment areas of the planar membersand further so as to increase the stiffness of the planar members. Inanother aspect, the floor plane and the chassis plane are separated byapproximately the width of the elongate rail members and the elongatecross-tie members so as to define a floor that is positioned adjacentthe chassis.

[0018] Another aspect of the invention is a recreational vehiclecomprising: a chassis; a frame attached to a top face of the chassis;and a plurality of planar bulkheads attached along first edges to abottom face of the low profile frame and along second edges to sides ofthe chassis such that the planar bulkheads extend downwards from thechassis and low profile frame thereby defining a three-dimensional spaceframe. In one embodiment, the recreational vehicle further comprises aplanar, rigid storage area floor attached to second edges of the planarbulkheads opposite the first edges such that the interconnection of thevehicle frame, the planar bulkheads, and the storage area floor to thechassis encloses the chassis thereby defining a space frame structuresurrounding and including the chassis. In one embodiment, the chassis isa split-level chassis. The interconnection of the planar bulkhead andthe storage area floor defines storage areas that extend substantiallythe width of the recreational vehicle. The recreational vehicle furthercomprises a heating, ventilation, and air conditioning (HVAC) systeminstalled within and/or below the plane of the chassis.

[0019] In one embodiment, the recreational vehicle defines an interiorliving area wherein the vertical height of the interior living area isat least 7′6″ tall. The recreational vehicle also includes a slide-outroom. The slide-out room defines an interior slide out height whereinthe interior slide out height is at least 6′1″ high.

[0020] These and other objects and advantages of the present inventionwill become more fully apparent from the following description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is an isometric view of a vehicle frame mounted on apreassembled chassis forming the framework for a motorhome with a highinterior ceiling;

[0022]FIG. 2 is an exploded, isometric view of a partially assembledvehicle frame and a preassembled chassis;

[0023]FIG. 3 is a front, section view of a motorhome with the vehicleframe and a slide-out room in the extended position;

[0024]FIG. 4 is an assembled and exploded view of a heating,ventilation, and air conditioning (HVAC) system;

[0025]FIG. 5 is an isometric view of a completed motorhome including thevehicle frame; and

[0026]FIG. 6 is a top, section view of a motorhome illustrating oneembodiment of a floor plan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Reference will now be made to the drawings wherein like numeralsrefer to like parts throughout. FIG. 1 shows an assembled vehicle frame100 mounted to a preassembled chassis 102. The vehicle frame 100,mounted to the chassis 102 in the manner that will be described ingreater detail below, facilitates the construction of a motorhome 104(FIGS. 5 and 6) with a greater interior ceiling height, which in thisembodiment, is approximately 7′-6″. The vehicle frame 100 alsofacilitates building a slide-out 122 (FIGS. 3 and 6) with a greaterinterior height. The vehicle frame 100 also facilitates mounting ofrelatively massive items, such as generators, furnaces, storage andholding tanks, and the like low to the ground so as to provide a lowercenter of mass for the motorhome 104. The vehicle frame 100 provides astrong three dimensional space frame 118 to inhibit twisting of thevehicle frame 100 under torsional forces such as would arise when themotorhome 104 drives over uneven terrain so as to lift or drop a wheel116 with respect to the other wheels 116. The vehicle frame 100 furtherdefines integral storage areas 106 as part of the structure of thevehicle frame 100 in a manner that will be described in greater detailbelow. The vehicle frame 100 further facilitates routing of a heating,ventilation, and air conditioning (HVAC) system 110 below the beltlineof the chassis 102 so as to avoid intrusion of the HVAC system 110 intothe interior living space of the motorhome 104 to further enableincreased interior ceiling height of the motorhome 104 employing thevehicle frame 100.

[0028] As can be advantageously seen in FIG. 2, the chassis 102 of thisembodiment, is a split rail chassis 102 of a type known in the art. Thechassis 102 of this embodiment is a diesel pusher type and is availablefrom Freightliner, LLC. of Portland, Oregon as Model XL. The chassis 102comprises a pair of raised rails 112 and two pairs of lower rails 114.The raised rails 112 and lower rails 114 are rigid elongate membersformed of c-channel steel approximately 2¾″ by 9″ and approximately ¼″thick. The raised rails 112 and the lower rails 114 are allsubstantially parallel. A first and second end of each center rail 112overlies a lower rail 114 over a length of approximately 402″ and isattached along the overlying extent to the lower rail 114 in a knownmanner. Each pair of interconnected raised rails 112 and attached lowerrails 114 are displaced a lateral distance of approximately 34″ and arefurther interconnected by a plurality of orthogonally extendingcross-beams (not illustrated) rigidly attached so as to form a ladderframe structure of a type well known in the art.

[0029] The chassis 102 also comprises a plurality of road wheels 116with corresponding suspension, brake systems, steering, and drivemechanisms of types known in the art that are positioned atsubstantially the front and rear corners of the chassis 102 in themanner illustrated in FIG. 2. The road wheels 116 enable to themotorhome 104 to roll along the road and to be steered and braked in awell understood manner. The road wheels 116 are positioned adjacent theoverlapping raised rails 112 and lower rails 114. The chassis 102further comprises an engine assembly, transmission, drive axle, fuelsystem, and electrical system (not illustrated) of types known in theart to provide the motive power for the motorhome 104. These items areadvantageously located substantially within the plane of the raisedrails 112 to lower the center of mass of the chassis 102 and thus themotorhome 104.

[0030] The chassis 102 of this embodiment is highly resistant to bendingalong longitudinal and transverse axes. However, the chassis 102, byitself, is susceptible to twisting along the plane of the longitudinaland transverse axes due to torsional forces that arise when a roadwheel(s) 116 at one corner of the chassis 102 is displaced either aboveor below the plane of the remaining road wheels 116.

[0031] The vehicle frame 100 also comprises a plurality of transverselyextending bulkheads 120 illustrated in FIGS. 1 and 2. The bulkheads 120are rigid, planar pieces of steel approximately 0.0897″ thick. Thebulkheads 120 are rectangular, triangular, or compound rectangular inshape as can be seen in FIG. 2. Approximately 2″ of the outer edges ofthe bulkheads 120 are folded via known sheet metal forming techniques soas to extend generally perpendicular to the major plane of the bulkheads120 thereby forming attachments areas 121 and also so as to increase thestiffness of the bulkheads 120.

[0032] The bulkheads 120 are fixedly attached along the attachment areas121 via bolts and welding in a known manner to sides of the chassis 102and the bottom of the vehicle frame 100 to further interconnect thechassis 102 and the vehicle frame 100. The bulkheads 120 are attached tothe vehicle frame 100 and the chassis 102 so as to extend downward fromthe vehicle frame 100 and the chassis 102. The rigid interconnection ofthe bulkheads 120 with the chassis 102 and the vehicle frame 100 boxesin the raised rails 112 and the lower rails 114 of the chassis withrigid plates thereby defining a three-dimensional space frame structure118 enclosing the chassis 102. The rigidly interconnected vehicle frame100 and chassis 102, boxed in by the bulkheads 120, are much moreresistant to twisting forces than the chassis 102 by itself.

[0033] The motorhome 104 of this embodiment is assembled on and aroundthe interconnected vehicle frame 100, the chassis 102, and the bulkheads120. The motorhome 104 provides users a vehicle with a variety of livingspaces and amenities fitted within the motorhome 104. The partitioningof the interior living spaces and fitment of interior amenities can bereadily implemented by one of ordinary skill in the art. One embodimentof interior partitioning and furnishing of the motorhome 104 isillustrated in FIG. 6. The construction and features of the motorhome104 will be described in greater detail below.

[0034] The motorhome 104 of this embodiment comprises a slide-out 122(FIGS. 3 and 6). The slide-out 122 is a movable structure containedwithin the motorhome 104 that is extensible between a retracted, travelposition and an extended, live-in position. The slide-out 122 is agenerally rectangular structure closed on the top and bottom and threesides and open on the remaining fourth side. The slide-out 122 of thisembodiment is approximately 3½′ wide, 13′-4″ long, and of 6′-2″ interiorheight. The slide-out 122, in the extended, live-in position, providesadditional interior living space to the users of the motorhome 104.

[0035] In particular, the slide-out 122 provides an additional 45½square feet of living space when the slide-out 122 is extended. Aparticular advantage of the slide-out 122 of this embodiment is that theinterior ceiling height is approximately 6′2″. This enables a person ofabove average height to stand up within the slide-out 122. This greatlyincreases the convenience and livability of motorhomes 104 employing thevehicle frame 100 which enables the slide-out 122 as herein described.As will be described in greater detail herein below, the increasedliving space in the main section of the motorhome 104 and in theslide-out 122 is due, in part, to the configuration of the vehicle frame100.

[0036] The slide-out 122 includes a slide-out mechanism 124. Theslide-out mechanism 124, of this embodiment, is an electro-mechanicalassembly of a type known in the art. In alternative embodiments, theslide-out mechanism 124 is a hydraulic mechanism. The slide-outmechanism 124 extends and retracts the slide-out 122 between theretracted, travel position and the extended, live-in position inresponse to user commands. The slide-out mechanism 124 also physicallysupports the slide-out 122 in transition between the travel and live-inpositions. The slide-out mechanism 124 of this embodiment offers greateruser friendliness than known mechanisms for extending slide-out roomswhich are hand actuated. The slide-out mechanism 124 of this embodimentis lighter and requires less maintenance than known hydraulic slide-outextension mechanisms.

[0037] The slide-out 122 and slide-out mechanism 124 are attached to thevehicle frame 100. The vehicle frame 100, when interconnected with thechassis 102 and the bulkheads 120 as previously described, is highlyresistant to bending and twisting. Thus, the slide-out 122 and slide-outmechanism 124, attached to the rigid structure of the vehicle frame 100has a low susceptibility to jamming or sticking due to flexing of themotorhome 104 as it is driven about. The slide-out 122 is also able tosupport a significant amount of weight, such as furniture and occupants.It should be appreciated that alternative embodiments of the inventioninclude additional slide-outs 122.

[0038] The vehicle frame 100 also comprises seat supports 126. The seatsupports 126 are rectangular structures formed from sheet steelapproximately ⅛″ thick and are approximately 12{fraction (13/16)}″ by22½″. The seat supports 126 are fixedly attached to the vehicle frame100 via a plurality of bolts and/or welding in a known manner adjacentthe front end of the vehicle frame 100. The seat supports 126 provide asupport and attachment structure for passenger seats 128 of known types.The passenger seats 128 provide seating accommodations for driver andpassengers in a known manner.

[0039] The vehicle frame 100 of this embodiment, also comprises twostorage area floors 130. The storage area floors 130 are rigid compositerectangular members approximately 3¼″ thick, 95″ wide, and 98″ long and3{fraction (1/4)}″ thick, 65″ wide, and 44″ long. The storage areafloors 130 are a composite of tube steel, foam, and Luan vacuum bondedtogether. The storage area floors 130 are fixedly attached along theattachment areas 121 along lower edges of the bulkheads 120 with weldingand bolts in a known manner. The storage area floors 130, together withthe bulkheads 120, define storage areas 106. The storage areas 106 ofthis embodiment extend substantially the full width of the motorhome104. The storage areas 106 of this embodiment are two rectangular spacesapproximately 95″ by 98″ by 25½″ and 65″ by 42″ by 25½″. The storageareas 106 of this embodiment are approximately 9″ higher than comparablestorage areas would be in an embodiment employing a straight rail designchassis. In particular, the raised rails 112 of the chassis 102 are 9″higher than the lower rails 114 and thus provide 9″ additional height tothe storage areas 106.

[0040] The storage area floor 130, comprising a rigid member fixedlyattached along the length of the lower edges of the bulkheads 120,further defines the three-dimensional structural space frame 118. Thestructural space frame 118, comprising a plurality of rigid panels andrigid elongate members fixedly interconnected along their adjoiningedges and arranged at right angles to each other, forms a structurallyrigid space structure. It will be appreciated that distorting the spaceframe 118 would require separation of the joints between componentmembers and/or bending of the rigid members. This further increases thetorsional rigidity of the interconnected vehicle frame 100, chassis 102,bulkheads 120, and storage area floor 130 assembly.

[0041] The vehicle frame 100 also comprises a plurality of storage areadoors 132 (FIG. 3). In one embodiment, the storage area doors 132 arerectangular, rigid structures approximately 2⅜″ thick by 25½″ by 8′long. The storage area doors 132 are a vacuum bonded composite offiberglass, Luan plywood, block foam insulation, and aluminum. Thestorage area doors 132 enclose the storage areas 106. The storage areadoors 132 have an insulation value of R11 and thus provide thermalinsulation to the interior of the storage areas 106. The storage areadoors 132 also retain objects placed in the storage areas 106 fromfalling out as the motorhome 104 moves about or from unintentionalremoval by curious children or thieves. The storage area doors 132 alsoinhibit intrusion of pests and windblown dirt, dust, and rain into theinterior of the storage areas 106 thereby befouling the interior andpossibly damaging items stored therein.

[0042] The storage area doors 132 are hingedly attached along either atop edge or a vertical edge of the storage area doors 132 to the vehicleframe 100. The storage area doors 132 can be raised to an elevatedposition to facilitate placing items into or removing items from theinterior of the storage areas 106. The storage area doors 132 arefurther positionable in a closed position to seal the interior of thestorage areas 106. The storage area doors 132, in a preferredembodiment, further comprise weather seals 133 and a latching mechanism135. The weather seals 133 are resilient, tubular structures of a typeknown in the art that are attached with adhesive to the periphery of thestorage area doors 132 on the side of the storage area doors 132 facingthe motorhome 104. The weather seals 133 improve the seal between thestorage area doors 132 and the storage areas 106 in a known manner. Thelatching mechanism 135 is a lock mechanism of a type well known in theart which lockably secures the storage area doors 132 in the closedposition to further inhibit unintentional opening of the storage areadoors 132.

[0043] As is illustrated in FIGS. 1 and 2, the vehicle frame 100comprises a floor section 101 which is formed from a plurality ofL-channel elongate members 174, C-channel elongate members 176, andsquare tubing elongate members 180. The L-channel elongate members 174of this embodiment are approximately 1½″ wide, 6⅜″ tall, and 34′ longand are made of sheet steel approximately 0.0897″ thick. The C-channelelongate members 176 of this embodiment are approximately 1½″ wide, 3½″tall, and 34′ long and are made of sheet steel approximately 0.0897″thick. The square channel elongate members 180 of this embodiment areapproximately 2″ square in cross section, approximately 97″ long, andare made of sheet steel with a wall thickness of approximately ⅛″. Itshould be appreciated that the configurations of the elongate members174, 176, 180 herein described are simply one embodiment and that otherconfigurations of the elongate members 174, 176, 180 could be employedby one of skill in the art without detracting from the spirit of thepresent invention.

[0044] The L-channel elongate members 174 and the C-channel elongatemembers 176 extend substantially the length of the vehicle frame 100.The C-channel elongate members 176 define a cavity 182 and the L-channelelongate members 174 define an inside corner 184 as illustrated in FIG.3, Detail B. The square channel elongate members 180 are fixedlyattached via welding in a known manner to the L-channel elongate members174 such that a first and second end of each square channel elongatemember 180 is flush with the inside corner 184 of an L-channel elongatemember 174 such that the two L-channel elongate members 174 areparallel, the plurality of square channel elongate members 180 extendperpendicular to each of the L-channel elongate members 174, and theplurality of square channel elongate members 180 are thus allrespectively parallel.

[0045] A C-channel elongate member 176 is fixedly attached via weldingin a known manner to each L-channel elongate member 174 such that theC-channel elongate member 176 abuts a first or second end of the squarechannel elongate members 180 and further such that the cavity 182 of theC-channel elongate member 176 is adjacent the L-channel elongate member174. Thus, the L-channel elongate members 174 enclose the cavities 182and thus create closed structures. The abutment of the C-channelelongate members 176 against the square channel elongate members 180inhibits displacement and bending of the square channel elongate members180 with respect to the L-channel 174 and C-channel 176 elongatemembers. The interconnection of the L-channel 174 and C-channel 176elongate members also defines two shelves 186 extending the length ofthe L-channel 174 and C-channel 176 elongate members. The interconnectedL-channel 174, C-channel 176, and square channel 180 elongate membersthus define a rigid ladder frame structure that is highly resistant tobending and flexing.

[0046] In one embodiment, additional L-channel 174 and C-channel 176elongate members are interconnected to form Z-channel elongate members190. The Z-channel elongate members 190 are formed by positioning anL-channel elongate member 174 overlying the C-channel elongate member176 such that the cavity 182 of the C-channel elongate member 176 isimmediately below and adjacent the inside corner 184 of the L-channelelongate member 174 and such that the L-channel 174 and C-channel 176elongate members are aligned with each other. The L-channel 174 andC-channel 176 elongate members are then attached via welding in a knownmanner to form the Z-channel elongate members 190. The Z-channelelongate members 190 extend longitudinally and are positioned so as tobe parallel to, aligned with, and between the raised rails 112. TheZ-channel elongate members 190 are substantially the same length as theraised rails 112.

[0047] The motorhome 104 also comprises a coach floor 134. The coachfloor 134 of this embodiment is formed from a plurality of rectangularpieces of ¾″ tongue and groove plywood, placed so as to abut each otherin a coplanar fashion. The coach floor 134 is a planar, rectangularstructure approximately 97¼″ by 420⅝″. The coach floor 134 is placeddirectly on the floor section 101 of the vehicle frame 100 so as to reston the shelves 186. The coach floor 134 is attached to the floor section101 of the vehicle frame 100 via a plurality of screws and adhesive in aknown manner. The coach floor 134 provides a continuous flooring surfacefor the motorhome 104 to support occupants and furniture in the interiorof the motorhome 104. The coach floor 134 also provides a support andattachment surface for padding, carpeting, tile, linoleum, or otherinterior floor finishings.

[0048] As is illustrated in FIGS. 1 and 2, the floor section 101 of thevehicle frame 100 is mounted such that the bottom surface of the floorsection 101 is positioned directly on the raised rails 112. As such, thecoach floor 134 is elevated above the raised rails 112 of the chassis102 by a distance substantially equal to the thickness of the memberscomprising the floor section 101. This results in the upper surface ofthe coach floor 134 being located lower than the upper surfaces offloors in other motorhomes thereby allowing for greater availableinterior height in the motorhome 104 and also in a lowering of thecenter of gravity of the motorhome 104 of this embodiment.

[0049] Similarly, as is illustrated in FIGS. 2 and 3, the slide outmembers 124 are mounted within the floor section 101 of the vehicleframe 100. As such, the floor of the slide out 122 is located atapproximately the same height as the floor 134 of the main part of themotorhome 104. This results in the floor of the slide out 122 of themotorhome 104 being located lower than the floor of slide outs inmotorhomes of the prior art. Hence, the height of the available spacewithin the slideout 122 within the motorhome 104 is further increased.

[0050] Moreover, the floor section 101 is attached to the upper surfaceof the raised rails 112 and is also connected to the sides and thebottom side of the raised rails 112 and the lower rails 114 via thebulkheads 120 that are also connected to the floor section 101. As isillustrated in FIGS. 1 and 2, the floor section 101 is coupled to theraised rails 112 and the lower rails 114 at periodic intervals along thelength of the floor section 101 of the vehicle frame 100. Byinterconnecting the floor section 101 to the raised rails 112 and thelower rails 114 using the space frame 118 that encloses the raised rails112 and the lower rails 114 along the top and sides and, in someinstances, the bottom, twisting of the frame 100 when the wheels 116 ofthe motorhome 104 are vertically displaced from each other is reduced.Further, forming the floor section 101 so that the longitudinal membersare interconnected by lateral members further reduces twisting orbending of the vehicle frame 100 when the front and rear wheels 116 aredisplaced with respect to each other.

[0051] The motorhome 104 also comprises coach walls 136. The coach walls136 are generally planar, rectangular structures approximately 2⅜″thick, 90″ tall, and 416 ⅞″ long. The coach walls 136 are made from alaminated composite of fiberglass, phenolic Luan plywood, 2″ block foaminsulation, and interior decor panel which are vacuum bonded togetherwith an aluminum frame. The coach walls 136 provide physical structureto the motorhome 104. The coach walls 136 also insulate the interior ofthe motorhome 104 against heat transfer and sound. The coach walls 136,of this embodiment, are approximately ½″ thicker than walls typicallyused in the art and have a higher insulation rating than other knownwalls. The insulation rating of the coach walls 136 of this embodimentis R11. The coach walls 136 also comprise various openings toaccommodate windows, doors, slide-outs 122, vents, etc. the formationand placement of which are readily realized by one skilled in the art.

[0052] The motorhome 104 also comprises a coach roof 140. The coach roof140 is a planar, rectangular structure approximately 97¼″ wide by 371″long. The coach roof 140 is formed from a laminate of a rubber outerroofing layer, Luan plywood, ultra-light high-density block foaminsulation core, and a one-piece carpeted inner ceiling layer bondedwith an extruded aluminum welded superstructure 138.

[0053] The coach roof 140 is substantially planar along a lower face 142and convexly curved along an upper face 144. The coach roof 140 isapproximately 5½″ thick at the thickest region near the center of thecoach roof 140 and convexly tapers off to the sides and towards thefront and back to a thickness of approximately 2½″ along the edges ofthe coach roof 140. Thus, the upper face 144 of the coach roof 140 has acrowned contour. The crowned contour of the upper face 144 of the coachroof 140 inhibits pooling of water and accumulation of snow and debrison the coach roof 140. Thus, the motorhome 104, fitted with the coachroof 140 as herein described, can more readily shed water, snow, anddebris and minimize the deleterious effects of retaining water or debrisin contact with the materials of the coach roof 140. The crowned contourof the upper face 144 also improves the structural durability of thecoach roof 140 because avoiding accumulation of water and snow willminimize the vertical weight loads of heavy snow or water which couldpotentially otherwise bow the coach roof 140 leading to distortion,cracking, or separation of joints. The crowned contour of the coach roof140 also improves the aesthetics of the motorhome 104 because morereadily shedding debris helps to minimize adhesion of dirt and thusmaintains a cleaner appearance to the exterior of the motorhome 104.

[0054] The motorhome 104 also comprises a plurality of attachmentassemblies 146. The attachment assemblies 146 are extruded from aluminumalloy in a known manner. The attachment assemblies 146 are elongatemembers that extend substantially the length of the motorhome 104. Theattachment assemblies 146 interconnect the coach walls 136, the storagearea doors 132, the coach roof 140, and the vehicle frame 100 in amanner that will be described in greater detail below.

[0055] As viewed in a perpendicular cross-section (as shown in FIG. 3)the attachment assemblies 146 comprise a planar attachment area 150, ahollow rounded, closed rectangular channel 152 region, and an innerpartition 154. It should be appreciated that the attachment assemblies146 are unitized, extruded assemblies and the planar attachment area150, the rectangular channel 152, and the inner partition 154 hereindescribed are regions of the attachment assemblies 146 and arematerially and structurally continuous with each other.

[0056] The attachment area 150 is a rectangular, planar region of theattachment assemblies 146 approximately 2⅛″ by 371″ and extendsvertically from the rectangular channel 152 approximately 2⅛″ andprovides a convenient structure for attaching the attachment assemblies146. The rectangular channel 152 is a closed, structural element of theattachment assemblies 146 approximately 2″ by ¾″ and increases thestiffness of the attachment assemblies 146 to bending and twistingaccording to well understood structural principles. The inner partition154 extends vertically approximately ⅝″ within the rectangular channel152 and spans and internally partitions the rectangular channel 152 andfurther stiffens the attachment assemblies 146. The inner partition 154is substantially coplanar with the attachment area 150.

[0057] The attachment assemblies 146 are fixedly attached to an upperand lower edge of the coach walls 136 such that the rectangular channels152 are positioned between outer layers of the coach walls 136 as shownin FIG. 3, details A and B. The attachment assemblies 146 are furtherattached to the coach walls 136 such that the rectangular channels 152are positioned flush with upper and lower edges of the coach walls 136.The attachment areas 150 of the attachment assemblies 146 thus extendbeyond the edges of the coach walls 136 approximately 2⅛″. Theattachment assemblies 146 are attached to the coach walls 136 with anadhesive, such as MA425 from Plexus of Danvers, Mass. in a known manner.

[0058] The coach walls 136 with the attachment assemblies 146 attachedare placed on the coach floor 134 such that the attachment area 150 isadjacent the edge of the coach floor 134 and the rectangular channel 152rests on the coach floor 134. This placement of the coach walls 136 andattached attachment assemblies 146 results in the edge of the coachfloor 134 occupying the corner defined between the attachment area 150and the rectangular channel 152. This placement further results in thecoach walls 136 straddling the coach floor 134 such that approximatelyhalf of the thickness of the coach walls 136 is overlying the coachfloor 134. This enables the coach walls 136 to partially rest on thecoach floor 134 for additional vertical load support while stillmaintaining clearance for recessed attachment of the coach walls 136such that the attachment devices do not protrude beyond the outer faceof the coach walls 136.

[0059] The attachment assemblies 146 are attached to the coach floor 134and the vehicle frame 100 via a plurality of screws 156 positionedapproximately every 5″ along the length of the attachment assemblies146. The screws 156 of this embodiment are 10-16×1″ of a type known inthe art and installed in a known manner.

[0060] The coach roof 140 is positioned on the coach walls 136 such thatthe attachment areas 150 are adjacent the edges of the coach roof 140and such that the coach roof 140 partially overlies the coach walls 136.The attachment areas 150 are attached to the coach roof 140 via aplurality of screws 156 placed approximately every 5″ along the lengthof the edges of the coach roof 140.

[0061] The motorhome 104 also comprises a plurality of trim pieces 160.The trim pieces 160 are elongate members of semi-rigid material, such asvinyl, approximately 20′ long, 5″ wide and {fraction (1/16)}″ thick. Thetrim pieces 160 are arcuate in cross section and are attached to thealuminum superstructure 138 via a friction fit achieved in a knownmanner. The trim pieces 160 are positioned to abut each other so as toextend the full length of the coach roof 140. The outer rubber roofinglayer of the coach roof 140 overlies the trim pieces 160.

[0062] The trim pieces 160 cover the screws 156 attaching the coach roof140 to the coach walls 136. The trim piece 160 obscures the view of thescrews 156 to thereby improve the aesthetics of the motorhome 104. Thetrim piece 160 also shields the screws 156 and the upper edges of thecoach walls 136 from rain, snow, and debris. Thus the trim piece 160inhibits accumulation of water and debris adjacent the screws 156 andthe upper edges of the coach walls 136 so as to inhibit corrosion andfouling of the screws 156 and the coach walls 136. The trim piece 160also inhibits intrusion of water and debris into the interior of thecoach walls 136 which could compromise the strength and structuralintegrity of the coach walls 136.

[0063] The HVAC system 110 comprises an air conditioning unit 162, afurnace 164, a manifold 166, a duct 170, and at least one register 172as illustrated in FIG. 4. The air conditioning unit 162 cools incomingair and provides the cool air for cooling the interior of the motorhome104 in a known manner. The furnace 164 warms incoming air and provideswarm air for warming the interior of the motorhome 104 also in a knownmanner The air conditioning unit 162 or the furnace 164 can be activatedin response to user commands in a known manner. The manifold 166receives air from both the air conditioning unit 162 and the furnace 164and routes the air to the duct 170. The duct 170 extends substantiallythe length of the interior of the motorhome 104. The duct 170 carriesthe warm or cool air to at least one register 172. The registers 172communicate with the duct 170 in appropriate locations and direct coolor warm air, received from the duct 170, into the interior of themotorhome 104. The registers 172 includes a screen to inhibit objectsfalling into the interior of the registers 172 and the duct 170.

[0064] The HVAC system 110, of this embodiment, is located within orbelow the plane of the chassis 102. Positioning the air conditioningunit 162 and the furnace 164, which are both relatively heavy items,within or below the plane of the chassis 102 further lowers the centerof mass of the motorhome 104 to thereby improve the road handling of themotorhome 104. The placement of the HVAC system 110 of this embodimentalso distances the duct 170 and registers 172 from the coach roof 140.Other known motorhome designs rout HVAC ducting adjacent the roof of thevehicle which exposes the cool air to thermal heating from sunlightincident on the roof of the vehicle. In the motorhome 104 of thisembodiment, the duct 170, register 172, and air conditioning unit 162are shaded from incident sunlight by the motorhome 104. Thus, the HVACsystem 110 can more efficiently provide cool air to the interior of themotorhome 104. This improves the occupant's comfort in hot weather andreduces fuel costs for powering the HVAC system 110.

[0065] A further advantage of the HVAC system 110 of this embodiment isthat the air conditioning unit 162, duct 170, and register 172 whichcarry cool air are located below the living space of the motorhome 104.As is well understood by those of ordinary skill in the art, a coolerthan ambient surface, such as the air conditioning unit 162, duct 170,and register 172 induces liquid water to condense out of the atmosphereif the temperature of the surface is at or below the dew point. When airconditioning ducting is routed above the living space of a motorhome,liquid water that condenses on the ducting is drawn downwards bygravity. This can induce liquid water to intrude into walls, ceilings,and other interior materials. It can be appreciated that liquid watercan readily damage the structural integrity of typical motorhomebuilding materials. Liquid water can also stain and warp interiormaterials, damaging the aesthetics of a motorhome. The air conditioningunit 162, duct 170, and registers 172 of this embodiment are positionedbelow the living space of the motorhome 104 and thus water thatcondenses out during use of the HVAC system 110 is drawn downwards andaway from the motorhome 104 without intruding into the living spaces ofthe motorhome 104.

[0066] An additional advantage of the HVAC system 110 of this embodimentis that placement of the HVAC system 110 adjacent and below the beltlineof the chassis 102 obviates the need to place portions of an HVAC systemon the roof of the motorhome 104. Other known HVAC systems placeportions of the system on the exterior roof of a motorhome. Thisrequires that the major plane of the outer roof be lowered with respectto the roof of the present invention so as to maintain the overallheight restrictions previously mentioned. Lowering the exterior roofheight results in corresponding lowering of the interior ceiling heightand a corresponding reduction in the interior space and livability ofsuch a motorhome.

[0067] Yet another advantage of the HVAC system 110 of this embodimentis that placement of the HVAC system 110 adjacent and below the beltlineof the chassis 102 distances the furnace 164 and air conditioning unit162 from the interior of the motorhome 104. The air conditioning unit162 and furnace 164 are relatively noisy in operation. Placing the HVACsystem 110 outside the interior of the motorhome 104 distances the noisesources of the air conditioning unit 162 and the furnace 164 and thusprovides a quieter, more comfortable living environment for users of themotorhome 104.

[0068] Another advantage of the vehicle frame 100 is that theinterconnected vehicle frame 100, bulkheads 120, and storage area floor130 together define the rigid, three-dimensional space frame 118. Thespace frame 118 can be readily constructed as a stand-alone structuralentity separate from the chassis 102 as will be well understood by oneskilled in the art following consideration of the specification hereindisclosed. Assembling the space frame 118 independently from the chassis102 facilitates assembling the space frame 118 onto the chassis 102after the space frame 118 is completed. This facilitates a just-in-timedelivery of the chassis 102 and thus avoids tying up valuable capital inthe manufacture of the motorhome 104. The chassis 102 is a significantmaterial cost of the motorhome 104 and it will be appreciated that ajust-in-time delivery can reduce the construction costs of the motorhome104, thus providing lower cost to the end consumer and/or increasedprofit margins for the manufacturer of the motorhome 104.

[0069] Although the preferred embodiments of the present invention haveshown, described and pointed out the fundamental novel features of theinvention as applied to those embodiments, it will be understood thatvarious omissions, substitutions and changes in the form of the detailof the device illustrated may be made by those skilled in the artwithout departing from the spirit of the present invention.Consequently, the scope of the invention should not be limited to theforegoing description but is to be defined by the appended claims.

What is claimed is:
 1. A motorhome comprising: a chassis having at leasttwo parallel interconnected chassis members having top bottom and sidessurfaces and wherein the chassis further includes a plurality of wheelsattached thereto to permit rolling movement of the chassis over theground and wherein the chassis defines a location for an engine so thatthe motorhome can be self-propelled; a frame having a floor section anda plurality of bulkhead members that are mechanically coupled to thefloor section at spaced intervals so as to extend perpendicularlydownward from the floor section, wherein the floor section ismechanically coupled to the upper surface of the parallel interconnectedchassis members and wherein the plurality of bulkhead members aremechanically coupled to the side surfaces of the parallel interconnectedchassis members such that the frame is mechanically coupled to theparallel chassis members in at least two orthogonal directions; and ahousing mounted on the frame so as to define an enclosed living space,wherein the housing includes a bathroom, a bed and a driver's positionsuch that a driver can drive the motorhome.
 2. The motorhome of claim 1,wherein the floor section comprises at least a first and a secondlongitudinal member and a plurality of interconnecting members whereinthe plurality of interconnecting members interconnect the longitudinalmembers such that the longitudinal members are positioned in the samehorizontal plane.
 3. The motorhome of claim 2, further comprising afloor that is attached to the floor section such that the floor iselevated above the parallel interconnecting chassis members by adistance substantially equal to the thickness of the floor section. 4.The motorhome of claim 3, wherein the interior height of the motorhomeis approximately 7′6″.
 5. The motorhome of claim 3, wherein the interiorheight of the motorhome is no less than 6′ less that the overallexterior height of the motorhome.
 6. The motorhome of claim 3, whereinthe interior height of the motorhome is at least 55% of the overallexterior height of the motorhome.
 7. The motorhome of claim 3, whereinthe floor is attached to the floor section such that the floor iselevated above the parallel interconnecting chassis members by adistance substantially equal to the thickness of the longitudinalmembers.
 8. The motorhome of claim 3, further comprising a slide outassembly having at least one slidable member mounted in the floorsection and a floor attached thereto such that the floor of the slideout assembly is at substantially the same height as the floor attachedto the floor section of the motorhome.
 9. The motorhome of claim 8,wherein the at least one slidable member extends through an opening inthe first longitudinal member.
 10. The motorhome of claim 8, wherein theinterior height of the slide out assembly is approximately 6′1″.
 11. Themotorhome of claim 1, wherein the plurality of bulkhead members comprisea plurality of planar members that have an opening formed therein suchthat the parallel interconnected chassis members are positioned withinthe opening such that the bulkhead members are mechanically connected tothe outer side surfaces of the parallel interconnected chassis memberswhile the floor section is mechanically coupled to the upper surface ofthe parallel interconnected chassis members.
 12. A motorhome framecomprising: a plurality of parallel, elongate rail members extending thelength of the frame; a plurality of parallel, elongate cross-tie membersattached perpendicular to the rail members and interconnecting the railmembers so as to define a chassis plane; and a plurality of rigid planarmembers fixedly attached along a first edge to the cross-tie and railmembers so as to extend downwards from the chassis plane wherein theinterconnected rail, cross-tie, and planar members together define athree dimensional space frame.
 13. The motorhome frame of claim 12,further comprising a rigid floor panel substantially parallel to thechassis plane and attached to a second edge of the planar membersopposite the first edge.
 14. The motorhome frame of claim 13, whereinthe interconnected elongate rail members, cross ties, planar members,and floor panel together define a closed, box structure.
 15. Themotorhome frame of claim 13, wherein the interconnected planar membersand floor panel define storage areas.
 16. The motorhome frame of claim15, wherein the storage areas extend substantially the width of thevehicle frame.
 17. The motorhome frame of claim 12, wherein the planarmembers are folded along edges of the planar members such that a portionof the planar members extend substantially perpendicular to the plane ofthe planar members so as to define attachment areas of the planarmembers and further so as to increase the stiffness of the planarmembers.
 18. A recreational vehicle comprising: a chassis; a low profileframe attached to a top face of the chassis; and a plurality of planarbulkheads attached along first edges to a bottom face of the low profileframe and along second edges to sides of the chassis such that theplanar bulkheads extend downwards from the chassis and the low profileframe thereby defining a three-dimensional space frame wherein thebulkheads connect to the sides of the chassis.
 19. The recreationalvehicle of claim 18 further comprising a planar, rigid storage areafloor attached to third edges of the planar bulkheads opposite the firstedges such that the interconnection of the vehicle frame, the planarbulkheads, and the storage area floor to the chassis encloses thechassis thereby defining a space frame structure surrounding andincluding the chassis.
 20. The recreational vehicle of claim 18, whereinthe chassis is a split-level chassis.
 21. The recreational vehicle ofclaim 19, wherein the interconnection of the planar bulkhead and thestorage area floor defines storage areas.
 22. The recreation vehicle ofclaim 21, wherein the storage areas extend substantially the width ofthe recreational vehicle.
 23. The recreational vehicle of claim 18,further comprising a heating, ventilation, and air conditioning (HVAC)system installed within and below the plane of the chassis.
 24. Therecreational vehicle of claim 23, wherein the HVAC system is installedbelow the plane of the chassis.
 25. The recreational vehicle of claim 18defining an interior living space wherein the vertical height of theinterior living area is at least 7′6″ tall.
 26. The recreational vehicleof claim 18, further comprising a slide-out room.
 27. The recreationalvehicle of claim 26, wherein the slide-out room defines an interiorslide out height wherein the interior slide out height is at least 6′1″high.